Stratospheric ozone depletion: catalytic halogen cycle (net) (CFCs release Cl· (and Br·) in stratosphere; catalytic cycles convert O3 and O atoms to O2)
jee-mainjee-advancedneet-ug
CFCs release Cl· (and Br·) in stratosphere; catalytic cycles convert O3 and O atoms to O2 without consuming the catalyst — net ozone loss.
What each symbol means
| Symbol | What it stands for |
|---|---|
| O | Atomic oxygen participating in catalytic cycles |
| O3 | Ozone in stratosphere (UV shield) |
| Cl· / Br· | Radicals from photodissociation of CFCs / halons |
When to use this
High-altitude UV provides energy for radical chemistry; detailed steps include Cl + O3 → ClO + O2 and ClO + O → Cl + O2.